Additive potentiation by co application of propofol and sevoflurane on GABA induced chloride current in cultured neurons from rat dorsal root ganglia

Ａｌｔｈｏｕｇｈｍａｎｙｈｙｐｏｔｈｅｓｅｓｏｆａｎｅｓｔｈｅｓｉａｈａｖｅｂｅｅｎｐｒｏｐｏｓｅｄ,ｉｎｃｌｕｄｉｎｇｅｎｈａｎｃｅｍｅｎｔｏｆｉｎｈｉｂｉｔｉｏｎａｎｄａｌｓｏｄｅｐｒｅｓｓｉｏｎｏｆｅｘｃｉｔａｔｏｒｙｓｙｎａｐｔｉｃｔｒａｎｓｍｉｓｓｉｏｎ,ｔｈｅｅｘａｃｔｍｅｃｈａｎｉｓｍｏｆａｃｔｉｏｎｏｆｇｅｎｅｒａｌａｎｅｓｔｈｅｔｉｃｓｏｎｔｈｅｃｅｎｔｒａｌｎｅｒｖｏｕｓｓｙｓｔｅｍｒｅｍａｉｎｓｕｎｄｅｆｉｎｅｄ1　Ｈｏｗｅｖｅｒ,ｓｐｅｃｉｆｉｅｄｔａｒｇｅｔｓｉｔｅｓｏｆａ…     

GABA受体对谷氨酸受体的调控机制研究

目的 研究γ-氨基丁酸（GABA）受体对离子型谷氨酸受体的调控机制。方法 采用细胞膜片钳电生理技术,以GABA、谷氨酸（Glu）刺激记录GABA受体及Glu受体离子通道介导的全细胞电流（IGABA,IGlu）,观察GABA对谷氨酸受体离子通道活性的调控;并以荷包牡丹碱（Bic）抑制IGABA、以SO2-4或葡萄糖酸根（gluconate-）代替Cl-,研究其抑制作用的分子机制。结果 相同浓度GABA与Glu共给药诱导IGABA+Glu较单独给药诱导电流IGABA与IGlu之和小,该差异随浓度升高而降低;不同浓度GABA对Glu 30μmol/L诱导电流IGlu抑制作用随GABA浓度升高而增强,该抑制作用可以被Bic、SO2-4与gluconate-消除。结论 GABAA受体能抑制谷氨酸受体介导的全细胞电流,该作用具有浓度依赖性,其抑制机制可能与Cl-的通透性有关。     

利多卡因对大鼠海马锥体神经元GABA_A-Cl~-电流的影响

目的　研究利多卡因对大鼠海马锥体神经元全细胞γ 氨基丁酸介导的氯电流 (GABA Cl-电流 )的影响 ,及其中枢致惊厥作用的可能机制。方法　酶解急性分离 2周龄左右大鼠海马锥体神经元 ,采用全细胞膜片钳技术 ,记录利多卡因对单个海马锥体神经元GABA Cl-电流的影响。结果　将钳制电位固定在 - 6 0mV ,GA BA以剂量依赖性方式诱导出内向电流 ;利多卡因明显抑制GABA诱导的Cl-电流 (IGABA) ,5 0 %抑制浓度 (IC50 )为 4 .0 5mmol/L ,10mmol/L可使GABA浓度效应曲线明显右移 ,5 0 %有效浓度 (EC50 )由 7.72mmol/L增加到17.2mmol/L ,且最大电流明显降低。结论　利多卡因以非竞争性的方式 ,抑制海马锥体神经元GABAA Cl-电流 ,可能是其中枢致惊厥作用的机制。     

异丙酚与依托咪酯诱导对血浆皮质醇浓度的影响

目的　观察异丙酚与依托咪酯诱导对肾上腺皮质功能的影响。方法　在 2 0例择期手术麻醉的患者中分别对 2 m g/kg异丙酚与 0 .3 m g/kg依托咪酯诱导时血浆皮质醇浓度的变化进行观察。结果　异丙酚组给药后 2 h血浆皮质醇浓度由 (30 8.7± 2 7.4) nm ol/L降至 (2 6 7.7± 31.2 ) nm ol/L ,5 h后升高至 (4 0 0 .2± 2 6 .9) nm ol/L ,2 4h后恢复至给药前水平为 (30 6 .4± 35 .4) nm ol/L ;依托咪酯组给药后 2 h血浆皮质醇浓度由 (30 9.1± 36 .6 ) nm ol/L降至 (115 .9± 2 9.7) nm ol/L ,5 h时维持在 (171.1± 34.7) nm ol/L ,2 4h后恢复至给药前水平为 (311.8± 46 .2 ) nm ol/L。结论　异丙酚诱导对肾上腺皮质功能影响小 ,依托咪酯诱导则造成短暂的肾上腺皮质功能抑制。     

异丙酚对大鼠海马脑片突触长时程增强效应的影响

目的观察异丙酚对大鼠海马脑片突触长时程增强（LTP）效应的影响及其机制,以探讨其影响记忆的机制。方法雄性SD大鼠断头,取出海马组织,制备400μm厚度的海马脑片。采用细胞外微电极记录大鼠海马脑片CA1区细胞外群体峰电位（PS）,然后施以100Hz的高频强直刺激（HFS）,诱发LTP产生,观察异丙酚（1～100μmol／L）对大鼠海马脑片LTP的影响及其与γ-氨基丁酸（GABA）受体的关系。结果与正常对照组比较,给予异丙酚1、5μmnol／L,HFS后其PS幅值无明显改变（均P＞0．05）;给予异丙酚10、30、50、100μmol／L,HFS后其PS幅值均明显降低,分别为124％±9％、112％±8％、106％±7％、102％±6％（均P＜0．01）。给予印防己毒素50μmol／L＋异丙酚50μmnol／L、荷包牡丹碱10μmol／L＋异丙酚50μmol／L,HFS后其平均PS幅值分别为150％±11％、147％±11％,与HFS前比较,其PS的增幅明显增加（均P＜0．01）,与正常对照组比较,其PS的幅值差异无统计学意义（均P＞0．05）,与异丙酚50μmol／L组比较,其PS增幅明显增加（均P＜0．01）。给予CGP353485μmol／L＋异丙酚50μmol／L,HFS后PS的幅值无明显改变（P＞0．05）,与正常对照组比较,其PS的幅值明显降低（P＜0．01）,与异丙酚50μmol／L组比较,其PS幅值差异无统计学意义（P＞0．05）。结论异丙酚能够抑制海马LTP的形成而影响记忆功能,其作用机制与活化大鼠海马GABAA受体有关,而与GABAB受体无关。     

Stimulatory activity of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic receptors

Objective To study the activity of anti-peptide antibodies against the second extracellular loop of human M(2) muscarinic receptors on cAMP production and inward calcium currents (I(Ca)) in guinea pig ventricular myocytes.A comparison was also made with those of a muscarinic receptor agonist.Methods cAMP content was determined by radioimmunoassay and the I(Ca) in guinea pig single ventricular cells were recorded by the whole-cell patch clamp technique.Results Both the muscarinic receptor agonist, carbachol (Carb 10 μmol/L), and anti-peptide antibodies (Abs 100 nmol/L) could decrease basal cAMP levels (by 46.9%±4.2% and 60.2%±4.6%, respectively) and basal I(Ca).Both Carb (10 μmol/L) and Abs (100 nmol/L) could also inhibit the isoprenaline-induced (Iso 0.8 μmol/L) increases in cAMP production (from 108.2±7.0 to 88.4±7.2 pmol/mg·protein/min for Carb and 88.6±5.1 pmol/mg·protein/min for Abs, respectively) and the increases in I(Ca).The muscarinic receptor antagonist atropine (Atr) was able to prevent these effects of Carb and Abs.Conclusions Anti-peptide antibodies against an epitope located in the second extracellular loop of human M(2) muscarinic receptors, similar to muscarinic receptor agonist, could decrease the basal I(Ca) and β-receptor agonist stimulated increase of I(Ca) by decreasing the basal and β-receptor agonist stimulated increase of cAMP production, and therefore could have an effect on their target receptor.These results further suggest that autoimmunity may participate in the pathogenesis of human cardiomyopathy and the second extracellular loop of human M(2)muscarinic receptor could be the main immunodominant region.     

异丙酚对新生大鼠延髓脑片吸气呼吸神经元活动的影响

目的 观察异丙酚对延髓基本呼吸中枢吸气呼吸神经元放电活动的作用规律及其可能的作用机制。方法 以改良的Kreb氏液灌流新生SD大鼠离体延髓脑片，随机分成Ⅰ～Ⅵ组(每组n=6)。Ⅰ组为对照组(modified Kreb’s Solution，MKS组)，第Ⅱ～Ⅴ组异丙酚浓度分别为5、20、50和100μmol／L持续灌流3min，第Ⅵ组给γ-氨基丁酸A受体特异性阻断剂荷包牡丹碱(bicuculline，20μmol／L)与异丙酚20μtmol／L，观察给药后l、3、5、10、15、30min时呼吸吸气神经元放电时程和峰值、呼气时程(吸气神经元放电静止期)和呼吸频率活动的变化。结果(1)第Ⅱ～Ⅴ组在l-30min内吸气神经元放电时程均表现为逐渐显著减小，15min时作用最显著，且各组与MKS灌流的对照组相比均有显著性差异。(2)RI、第Ⅱ～Ⅴ组lmin内呼气时程无显著性变化，3～30min内呼气时程均表现为显著延长，5-15min内达到其最大效应。(3)在给药后的30min内放电峰值呈现先增加然后降低的趋势，各组间放电峰值无显著性差异。(4)给予异丙酚3～30min内呼吸频率逐渐减慢，5-15min内达到其最大抑制效应，各组问呼吸频率的变化无显著性差异。(5)Ⅵ Ⅳ组的吸气时程与间给药前比无显著性差异。结论(1)异丙酚可抑制新生大鼠离体延髓脑片标本吸气神经元的放电时程，主要表现为吸气时程的缩短和呼气时程延长，且呼吸呈浓度依赖性。(2)GABAA受体在异丙酚对延髓基本呼吸中枢呼吸气吸神经元放电活动的抑制作用中可能起重要作用。     

Angiotensin Ⅱ type 1 receptor modulation of L-type calcium currents in guine a-pig ventricular cells

Objective To study the cellular mechanism of the effect of Ang Ⅱ on I(Ca,L)in sing le guinea-pig ventricular cells by using losartan and 1-(5-Isoquinolinylsulfo nyl)-2-Methyl-Piperazine (H-7) as the Ang Ⅱ type 1 receptor (AT(1)) inhibit or and protein kinase C inhibitor, respectively.Methods Patch clamp techniques were used to study the cellular mechanism of the effect o f Ang Ⅱ on I(Ca,L) in single guinea-pig ventricular cells.Results In the whole cell patch clamp recording model, Ang Ⅱ stimulated I(Ca,L) in a concentration dependent manner; the maximal effect was obtained at 100 nmol/ L (n=9). At 30 nmol/L, Ang Ⅱ stimulated peak I(Ca,L) from 11.3±0.6 pA /pF to 15.3±0.6 pA/pF (at +10 mV, n=9, P<0.05). 100 nmol/L Losartan, a specific AT(1) receptor inhibitor, had no effect on I(Ca,L) (n=9), but th e effect of Ang Ⅱ on I(Ca,L) was inhibited by 100 nmol/L Losartan. Ang Ⅱ on I(Ca,L) was also inhibited by 20 μmol/L H-7, a specific protein kinas e C inhibitor, whereas H-7 alone has no effect on I(Ca,L) (n=9).Conclusion Ang Ⅱ stimulates I(Ca,L) in guinea-pig ventricular cells by binding to AT 1 through a transduction pathway involving protein kinase C.     

褪黑激素对新生大鼠海马神经元延迟整流钾电流的影响

目的 用膜片钳技术观察褪黑激素对电压门控性延迟整流钾电流(Ik)的影响,探讨褪黑激素在中枢神经系统的作用机制及其生物学意义.方法 选择7～12 d原代培养的新生Wistar大鼠海马锥体神经元,用膜片钳电压钳全细胞记录模式观察Ik的基本电生理特点,并观察不同浓度褪黑激素,包括1、10、100 nmol/L、1、10、100 μmol/L和1 mmol/L对Ik的幅度及动力学特性的影响.结果 利用海马锥体神经元的钾电流对4-AP、TEA的敏感性及电生理特性的不同可分离出激活、失活缓慢,具有强烈外向整流特性的延迟整流钾电流.褪黑激素对海马锥体神经元Ik的影响是快速、可逆、呈电压依赖性的,但对其激活曲线没有影响.褪黑激素对Ik的作用具有浓度依赖性.1～100nmoI/L的褪黑激素可逐渐递增地增加Ik幅度;1～100 μmol/L褪黑激素对Ik的增加程度随浓度增加而增大,而1 mmol/L褪黑激素的增加程度却减小.结论 褪黑激素可逆地增强体外培养新生大鼠海马神经元的Ik电流,这或许参与了神经元损伤和记忆损害的某些环节.     

Modulation by Divalent Cations of GABAρ1 Receptor From Human Retina Expressed in Xenopus Oocytes

ＩＮＴＲＯＤＵＣＴＩＯＮγ ａｍｉｎｏｂｕｔｙｒｉｃａｃｉｄ (ＧＡＢＡ)ｆｕｎｃｔｉｏｎｓａｓａｎｉｎｈｉｂｉｔｏｒｙｎｅｕｒｏｔｒａｎｓｍｉｔｔｅｒｉｎｔｈｅｍａｍ ｍａｌｉａｎｃｅｎｔｒａｌｎｅｒｖｏｕｓｓｙｓｔｅｍ .Ｉｎｉｔｉａｌｌｙ,ＧＡＢＡｒｅｃｅｐｔｏｒｓｗｅｒｅｄｉｖｉｄｅｄｉｎｔｏｔｗｏｗｅｌｌ ｃｈａｒａｃ ｔｅｒｉｚｅｄｒｅｃｅｐｔｏｒｔｙｐｅｓ,ＧＡＢＡＡａｎｄＧＡＢＡＢｒｅｃｅｐｔｏｒｓ.Ａｔｈｉｒｄｔｙｐｅｗａｓｄｉｓｃｏｖｅｒｅｄｉｎｂｒａｉｎａｎｄｒｅｔｉｎａ,ａｎｄｗａｓ…     

不同雌激素水平对大鼠血管内皮细胞功能及血管内皮细胞粘附分子1表达的作用

目的研究雌激素对雌鼠肺血管内皮细胞功能及血管内皮细胞粘附分子-1(VCAM-1)表达的调节。方法（1）雌性SD大鼠24只分为假手术组、去势组、治疗组,采用放射免疫法检测血清中内皮素、前列环素的含量,铜-镉还原法测定血清中一氧化氮的产量。放射配体结合法检测肺血管内皮细胞中雌激素受体含量。（2）正常雌鼠肺培养的第2代血管内皮细胞,按不同浓度17-β雌二醇(17-βE2)分为A组（对照）、B组（3×10-8mol/L17-βE2）、C组（3×10-7mol/L17-βE2）;D组（3×10-6mol/L17-βE2）、E组（3×10-6mol/L17-βE2+3×10-6mol/L他莫西芬）处理48h,白细胞介素-1β作用后流式细胞仪分别检测各组VCAM-1表达量。结果(1)去势组雌鼠血中一氧化氮（18μmol/L±8μmol/L）、前列环素（8.5pg/ml±2.5pg/ml）均降低,治疗组二者水平明显升高（31μmol/L±7μmol/L,P<0.05;10.9pg/ml±3.4pg/ml）,而内皮素含量变化则相反（170pg/ml±39pg/ml;100pg/ml±32pg/ml,P<0.05）。(2)去势组雌鼠血管内皮细胞中雌激素受体含量(fmol/106cell）显著降低（6.7±0.5),治疗组雌激素受体含量维持在高水平（17.6±1.2,P<0.01）。(3)白细胞介素-1β作用后A组表达VCAM-1细胞百分率明显增高（17.5%±1.5%）,B、C、D组表达VCAM-1细胞百分率显著降低（15.4%±1.42%、12.4%±0.34%、8.7%±0.27%,P<0.01）。结论雌激素水平可明显影响雌鼠血管内皮细胞内皮素、一氧化氮、前列环素的分泌,并可影响雌鼠血管内皮细胞中雌激素受体含量。雌二醇均可降低白细胞介素-1β诱发的雌鼠血管内皮细胞VCAM-1表达增高。     

七氟烷增强单个培养鼠背根神经节细胞γ-氨基丁酸调控的氯电流

采用膜片钳全细胞记录和"Y型管"技术,观察七氟烷(0．38×10-3～3×10-3mo1／L)对单个培养SD鼠背根神经节细胞3×10-6mol/Lr-氪基丁酸(GABA)调控的氯电流影响,实验结果发现,0．38×10-3,0．76×l0-3,1．52×10-3,2．28×10-3,3．04×10-3mol/L七氟烷分别增强氯电流峰值高度至对照值的(149±25)％,(203±27)％,(327±79)％,(331±109)％,(243±71)％。实验结果提示,临床麻醉浓度的七氟烷能增强培养鼠背根神经节细胞3×10-6mol/LGABA调控的氯电流。     

Effects of catecholamine-β-adrenoceptor-cAMP system on severe patients with heart failure

Objective To investigate the association between catecholamine-β-adrenoceptor (β-AR)-adenosine 3’, 5’-monophosphate (cAMP) system and long-term　prognosis in patients with chronic heart failure (CHF).Methods The study population comprised 73 patients with CHF (EF: 23%±10%) with a mean follow-up of 3.8±1.9 years. Plasma levels of norepinephrine (NE) were measured using high performance lipid chromatography, β-adrenergic receptor density (Bmax) and the content of cAMP in peripheral lymphocytes were calculated using 3H-dihydroalpneolo as ligand and competitive immunoassay, respectively. Deaths due to cardiovascular events within the follow-up period were registered.Results The total mortality was 64.7%, 57.4% of which was for cardiogenic (worsening heart failure: 32.4%; sudden death: 25.0%). In the cardiogenic death group, plasma levels of NE and epinephrine (E) (3.74 nmol/L±0.09 nmol/L and 3.17 nmol/L±1.0nmol/L) and the contents of peripheral lymphocyte cAMP (3.64 pmol/mg protein±1.4 pmol/mg protein) were significantly increased as compared with the survival group (2.68 nmol/L±0.07 nmol/L, 2.41 nmol/L±0.24 nmol/L and 2.73 pmol/mg protein±0.9 pmol/mg protein, respectively, all P&lt;0.01). In the sudden death group, plasma levels of NE and E (5.01 nmol/L±0.06 nmol/L and 4.13 nmol/L±0.08 nmol/L) were significantly increased as compared with the worsening heart failure group (2.49 nmol/L±0.07 nmol/L and 2.33 nmol/L±0.8 nmol/L, all P&lt;0.001) and to the survival group (2.68 nmol/L±0.07 nmol/L and 2.41 nmol/L±0.14 nmol/L, all P&lt;0.01). The incidences of sudden death were 0%, 75%, and 100% (χ2=16.018, P&lt;0.01) in patients with plasma NE&lt;2.5 nmol/L, NE 2.5 nmol/L-4.5 nmol/L, and NE&gt;4.5 nmol/L, respectively. In the worsening heart failure group, the content of peripheral lymphocyte cAMP (4.46 pmol/mg protein±0.18 pmol/mg protein) was significantly increased compared with the sudden death group (2.39 pmol/mg protein±0.9 pmol/mg protein, P&lt;0.001) and to the survival group (2.73 pmol/mg protein±1.1 pmol/mg protein, P&lt;0.001). The worsening heart failure death occurences were 5.0%, 72.2%, and 100% (χ2=14.26, P&lt;0.01) in patients with a content of peripheral lymphocyte cAMP &lt;2.5 nmol/L, cAMP 2.5 nmol/L-4.5 nmol/L, and cAMP&gt;4.5nmol/L, respectively. Bmax in peripheral lymphocyte was not significantly different (P&gt;0.05) among the sudden death, worsening heart failure, and survival groups in CHF patients.Conclusions Plasma levels of catecholamine increase significantly, and Bmax and the contents of cAMP in peripheral lymphocytes decrease significantly in patients with CHF. High plasma catecholamine levels may be associated with sudden death, and high intralymphocyte cAMP content may be associated with worsening heart failure in CHF patients.     

醛固酮对系膜细胞合成纤溶酶原激活剂抑制物-1的影响

目的 探讨醛固酮及阻断其受体后对系膜细胞生成纤溶酶原激活剂抑制物1（PAI-1）的影响。方法 醛固酮单独刺激大鼠系膜细胞24h以及采用螺内酯阻断后,用RT-PCR观察系膜细胞PA1-1mRNA的变化;用Western印迹方法检测细胞上清液中的PA1-1;采用ELISA方法测定细胞上清液中转化生长因子p1（TGF-β1）的含量;采用激光共聚焦检测系膜细胞内的活性氧（ROS）水平。观察不同浓度及不同作用时间的醛固酮刺激系膜细胞对PA1-1mRNA的影响。结果 醛固酮使系膜细胞PA1-1mRNA及蛋白表达明显升高,同时升高了TGF-β1的表达和细胞内的ROS水平。醛固酮使PA1-1mRNA表达呈剂量依赖性增加。100nmol／L醛固酮刺激系膜细胞4h后PA1-1mRNA表达才明显增加。加用螺内酯后使升高的PA1-1、TGF-β1表达以及细胞内ROS恢复到正常水平。结论醛固酮能独立促进大鼠系膜细胞分泌PA1-1的增加,同时醛固酮使TGF-β1表达以及细胞内ROS水平升高,而这些都是通过盐皮质激素受体介导的。     

Effect of Propofol on Glutamate and γ-aminobutyric Acid Release from Rat Hippocampal Synaptosomes

To investigate the effect of propofol on the release of glutamate and γ-aminobutyric acid (GABA) from rat hippocampal synatosomes, synaptosomes was made from hippocampus and incubated with artificial cerebrospinal fluid (aCSF). With the experiment of Ca²⁺-dependent release of glutamate and GABA, dihydrokainic acid (DHK) and nipectic acid were added into aCSF. For the observation of Ca²⁺-independent release of glutamate and GABA, no DHK, nipectic acid and Ca²⁺ were added from aCSF. The release of glutamate and GABA were evoked by 20 μmol/L veratridine or 30 mmol/L KCl. The concentration of glutamate and GABA in aCSF was measured by using high-performance liquid chromatography (HPLC), 30, 100 and 300 μmol/L propofol significantly inhibited veratridine-evoked Ca²⁺-dependent release of glutamate and GABA (P<0.01 orP<0.05). However, propofol showed no effect on elevated KCl-evoked Ca²⁺-dependent release of glutamate and GABA (P>0.05). Veratridine or elevated KCl evoked Ca²⁺-independent release of glutamate and GABA was not affected significantly by propofol (P>0.05). Propofol could inhibit Ca²⁺-dependent release of glutamate and GABA. However, it has no effect on the Ca²⁺-independent release of glutamate and GABA.     

Rapid determination of dopamine and its metabolites during in vivo cerebral microdialysis by routine high performance liquid chromatography with electrochemical detection

Objective To determine dopamine and its metabolites during in vivo cerebral microdialysis by routine high performance liquid chromatography with electrochemical detection.Methods Microdialysis probes were placed into the right striatum of Wistar rat brains and perfused with Ringer's solution at a rate of 1.5 μL/min.A reverse phase HPLC with electrochemistry was used to assay DA,DOPAC,and HVA after cerebral microdialysates were collected every 20 minutes from awake and freely moving rats.In order to identify the reliability of this method,its selectivity,linear range,precision and accuracy were tested and the contents of DA,DOPAC,and HVA in rat microdialysates were determined.Results The standard curve was in good linear at the concentration ranging from 74 nmol/L to 1.5 μmol/L for DOPAC(r2= 0.9996),from 66 nmol/L to 1.3 μmol/L for DA(r2=1.0000)and from 69 nmol/L to 1.4 μmol/L for HVA(r2=0.9992).The recovery of DOPAC(0.30,0.77,1.49 μmol/L),DA(0.26,0.69,1.32 μmol/L),and HVA(0.27,0.71,1.37 μmol/L)was 82.00±1.70%,104.00±4.00%,98.70±3.10%;92.30±1.50%,105.30±2.30%,108.00±2.00%;80.00±7.80%,107.69±8.00%,and 108.66±3.10%,respectively at each concentration.Their intra-day RSD was 3.3%,3.4%,and 2.5%,and inter-day RSD was 4.2%,2.3%,and 5.6%,respectively.The mean extracellular concentrations of DOPAC,DA,and HVA in rat brain microdialysates were 10.7,2.4,and 9.2 μmol/L(n=6),respectively.Conclusion The findings of our study suggested that the simple,accurate and stable method can be applied to basic researches of diseases related to monoamines neurotransmitters by cerebral microdialysis in rats.     

戊巴比妥和异丙酚制作大鼠局灶性脑缺血模型的对比研究

目的：比较戊巴比妥和异丙酚对大鼠局灶性脑缺血模型病理损伤的影响,评价异丙酚在大鼠局灶性脑缺血模型制作中的应用。方法：将30只雄性SD大鼠在戊巴比妥或异丙酚腹腔麻醉下制作成永久性大脑中动脉阻塞模型（n=15）。术后4 h参照改良的Bederson′s评分方法进行神经功能缺损评分,24 h采用TTC染色确定脑梗死体积,3 d行TUNEL和甲苯胺蓝染色分别测定半暗带内的凋亡细胞和存活神经元密度。结果： 神经功能缺损评分(1.46±0.98 vs 1.29±0.72),梗死体积［(37.8±4.95)% vs (31.1±5.09)% ］和半暗带内神经元密度［(740±24)个 /mm2 vs （794±23）个/mm2］在戊巴比妥组和异丙酚组间差异无统计学意义(P＞0.05),但异丙酚组半暗带内凋亡细胞的密度高于戊巴比妥组［（356±20） 个/mm2 vs （262±17） 个/mm2,P＜0.05］。结论： 异丙酚麻醉下制作大鼠局灶性脑缺血模型可获得与戊巴比妥相似的神经功能缺损评分、梗死体积和半暗带内存活神经元数量,但异丙酚能促进半暗带内的细胞凋亡。在评价一些药物或方法对局灶性脑缺血后细胞凋亡的影响时,应用异丙酚麻醉制作模型可能并不合适。     

Lead Can Inhibit NMDA^—,K^＋—,QA／KA—Induced Increases in Intracellular Free Ca^2＋ in Cultured at Hippocampal Neurons

Objective To examine the effects of Pb2+ on N-methyl-D-aspartate (NMDA)-, K+- and quisqualate(QA)/kainite(KA)-induced increases in intracellular free calcium concentration ([Ca2+]i) in cultured fetal rat hippocampal neurons in order to explain the cognitive and learning deficits produced by this heavy metal. Methods Laser scanning confocal microscopy was used. Results The results clearly demonstrated that adding Pb2+ before or after NMDA/glycine stimulation selectively inhibited the stimulated increases in [Ca2+]i in a concentration-dependent manner. In contrast, Pb2+ treatment did not markedly affect increases in [Ca2+]i induced by an admixture of QA and KA. The minimal inhibitory effect of Pb2+ occurred at 1 μ mol/L, and more than seventy percent abolition of the NMDA-stimulated increase in [Ca2+]iwas observed at 100 μmol/L Pb2+. Evaluation of pb2+-induced increase in [Ca2+]i response to elevating extracellular concentrations of NMDA, glycine or calcium revealed that Pb2+ was a noncompetitive antagonist of both NMDA and glycine, and a competitive antagonist of Ca2+ at NMDA receptor channels. In addition, Pb2+ inhibited depolarization-evoked increases in [Ca2+]i mediated by K+ stimulation (30 μmol/L), indicating that Pb2+ also depressed the voltage-dependent calcium channels. Also, the results showed that Pb2+ appeared to be able to elevate the resting levels of [Ca2+]i in cultured neurons, implying a reason for pb2+-enhanced spontaneous release of several neurotransmitters reported in several previous studies. Conclusion Lead can inhibit NMDA-, K+-, QA/KA-inducod increases in intracellular [Ca2+]i in cultured hippocampal neurons.     

alphastatin抑制体外内皮细胞血管生成及其作用机制的实验研究

目的探讨人纤维蛋白原α链末端的24个氨基酸片断alphastatin对人脐静脉来源内皮细胞(ECV304)血管生成抑制作用及机理。方法体外培养ECV304细胞,分别测定alphastatin对其迁移、增殖和体外管状结构形成的作用。用逆转录聚合酶链反应技术(RT-PCR)定性检测ECV304细胞中鞘氨醇激酶(SPK)mRNA的表达。分别以10、100、1000nmol/Lalphastatin处理ECV304细胞,提取细胞蛋白质,通过三磷酸腺苷(ATP)检测细胞SPK酶活性。结果不同浓度alphastatin处理组中ECV304细胞迁移的数目,分别为(103±4)个、(75±3)个、(13±1)个,低于对照组的(131±4)个,均P<0·05。alphastatin浓度为100nmol/L、1000nmol/L时,形成管状结构的面积分别为(1509±30)μm2/视野和(1301±20)μm2/视野,也明显低于对照组的(2996±31)μm2/视野,均P<0·05。alphastatin对ECV304细胞增殖的影响差异无统计学意义。RT-PCR证实ECV304细胞SPKmRNA的表达。与对照组比较,alphastatin降低ECV304细胞内1-磷酸鞘氨醇(S1P)生成量,当其浓度为100nmol/L,作用时间为12h时,效应最明显。结论体外实验证实alphastatin具有明显抑制ECV304细胞血管生成的作用,这种效应与降低细胞SPK活性、减少S1P的生成有密切关系。     

异丙酚对红细胞过氧化损伤的保护作用

目的：观察临床相关浓度异丙酚对红细胞过氧化损伤的保护作用。方法：采20例健康成人静脉血制成RBC悬液,分为空白对照组、过氧化氢（H2O2,100mmol/L）损伤组及3个损伤加不同浓度（分别为25,50及75μmol／L）异丙酚组,孵育后测定RBC悬液中K^ 、丙二醛（MDA）浓度和RBC溶血度。结果：孵育60min ,加异丙酚组K^ 浓度（0.16,0.14,0.14mmol/L）、MDA浓度(5.66,5.57,6.20nmol/L）和RBC溶血度（76.89%,59.84%,64.22%)与单纯损伤组（分别为0.26mmol/L,9.19nmol/L和100%）相比均显著降低,加异丙酚各组间及与空白对照组（0.10mmol/L,4.13nmol/L,52.73%）间无显著差别。结论：临床相关浓度的异丙H2O2损伤RBC可抑制DA生成,减少K^ 外流和降低溶血度,具有抗RBC过氧化损伤作用,但浓度依赖性不明显。